Costa scored his seventh Premier League goal of the season as Chelsea beat champions Leicester 3-0 at Stamford Bridge.
The Spain striker is one yellow card away from suspension and appeared to call for his own withdrawal midway through the second half. Had he been booked he would have missed next Sunday’s reunion with Jose Mourinho, when Manchester United visit.
Conte insisted it was his choice alone not to take off Costa and downplayed suggestions the striker was feeling his troublesome hamstrings.
“If I can, Costa I keep him until the end,” Conte said.
“I can take the risk about this, for a yellow card or for injury. I decide.
“Diego is in good shape. Costa is an important player to us.
“He has a good personality. We need his passion in every moment of the game.”
Overall Conte was happy with Chelsea’s second consecutive win and clean sheet adding:
‘In the first half we played a very good game with high intensity, good passing and finding the attackers between the lines,’ said Conte. ‘We created many chances to score and we were aggressive when we lost the ball.
‘Today I’m pleased because I saw the things we have been working on this week. Above all I’m pleased for the players because when you work so hard during the week it’s logical you want to see a good result and a good game.
‘Now we have a whole week to work and to see who is in the best shape to play the next match. The players know I want to see the right commitment and work-rate, after that I decide the formation. Another young player from the academy, Ola Aina, played his first (Premier league) game, and Nathaniel Chalobah showed he is really able.’
Our two most recent victories have come since Conte changed the formation to 3-4-3
‘I changed the system because when you arrive at a new team you need time to study the right fit for the team. After we conceded a lot of goals I decided to change before the Hull game. When I see my players during the week working this way I’m very calm.’